Sunday's NFL conference championships could tell us more than just who will be playing in Super Bowl XLVIII: they may provide exclamation points on that sexiest of matchups in the sport, the quarterback rivalry.

Two of the greatest signal callers in NFL history will face off in the AFC Championship game, New England’s Tom Brady and Denver’s Peyton Manning serving up the 15th instalment, and fourth in the playoffs, of what has been a compelling feud. Their teams are scheduled to meet again next season, but it remains to be seen whether the Broncos quarterback will still be around.

Meanwhile, in the NFC Championship game will come the first playoff meeting of what may turn out to be a rivalry just as big, if not bigger: Seattle Seahawks' Russell Wilson vs San Francisco 49ers' Colin Kaepernick. These two young tyros are at the beginnings of what could and should be illustrious careers. Kaepernick has already been to a Super Bowl. What is more, the pair play in the same division, giving their rivalry plenty of opportunities to develop.

If Sunday were to be the final Manning-Brady showdown, then there could be no more appropriate setting. The two quarterbacks have met just three times in the playoffs up to now, and yet between them they have dominated this stage. Sunday’s match-up will be the ninth AFC Championship Game in 13 seasons to feature at least one the two.

Discussion of their legacies invariably comes back to this same central argument: how should we balance team success against individual achievement? Manning has won the league’s Most Valuable Player award four times and looks like a shoo-in to take it yet again this year. But he has a losing record in the playoffs, and has come out on the wrong side in 10 of his 14 duels with Brady to date.

Of course, there is a good deal of nuance that gets lost along the way. Manning, despite moving from the Colts to the Broncos in 2012, has often had the good fortune to play with elite groups of receivers, be it Marvin Harrison and Reggie Wayne in Indianapolis, or the fearsome foursome of Demaryius Thomas, Wes Welker, Eric Decker and Julius Thomas in Denver. Brady has had great talent around him at times, too, but he has also fought through seasons such as this one, in which he has been obliged to work with an unfamiliar and inexperienced supporting cast.

On the other hand, the Patriots quarterback had other factors playing to his advantage early in his career. The New England teams that eliminated Indianapolis from the playoffs in 2003-04 and 2004-05 boasted the league’s first- and second-ranked defenses respectively. The Colts teams that they beat ranked 20th and 19th on that side of the ball.

Regardless of what happens on Sunday, the debate over who has been the greater quarterback will rage on. Even if the Patriots won it all this year, making Brady the third quarterback ever to own four Super Bowl rings, there would still be plenty of purists who continued to rank Manning ahead of him. Likewise, if the Broncos quarterback vanquished his old foe before steering Denver to victory at MetLife Stadium next month, there will always be those who argue that he should have won even more.

What we can say is that each player’s presence has ultimately been good for the other. It might not feel that way to Colts fans, as they reflect on those playoff eliminations to New England and wonder what might otherwise have been. Likewise, supporters in New England may dwell on the Super Bowl they might have won if it were not for a miraculous Manning-led second-half rally in the 2006-07 AFC Championship Game.

But great rivalries are the lifeblood of professional sport, a key part of why fans tune in to watch in the first place. The existence of Brady may have cost Manning championships, but it made the one he did win with the Colts so much more meaningful. Seven years later, it is telling that Indianapolis’s victory over Chicago at Super Bowl XLI is remembered far less vividly than that win over New England in the previous round.

Together Manning and Brady have driven one another to be better, raising the bar year after year. And they have certainly made one another richer – their high-profile rivalry helping both player's commercial endorsements to soar. Manning made a reported $12m from such deals last year, while Brady earned $7m.

There are many causes for the discrepancy between the two, not least Manning’s family ties. Having a father who used to play quarterback in the NFL, and a brother who continues to do so, does nothing to hurt his brand. But Manning has also cultivated an image that plays well to a mass audience.

Unlikely as it ought to be for a former first overall draft pick, Manning comes off as the everyman in this rivalry, a self-deprecating guy with a goofy sense of humour who married a girl that he met while still in college. The products he advertises are predominantly accessible goods like pizzas, cookies and credit cards. After Sunday’s win over San Diego, he told reporters that all he could think about was getting his hands on a Bud Light.

Brady, despite his underdog back-story – coming into the league as a sixth-round pick before getting thrust into action unexpectedly when Drew Bledsoe went down hurt in 2002 – has wound up at the opposite end of the spectrum. The products he endorses are often high-end, luxury goods like Ugg boots and Movado watches. His wife is a supermodel, and he recently told Women’s Health magazine that his favourite drink is a frozen margarita.

None of this provides any deep insight into either man’s true personality, of course. Their public images are at least in part a work of fiction, manipulated by marketing men in order to help them to win further endorsements. But what it does do is add layers to their rivalry, creating a narrative in which not only two players but two different characters are now being pitted against one another.

That there is an appetite for such contrasts has been evident from the build-up to this Sunday’s second match-up, the NFC Championship Game between the Seahawks and 49ers. As Brady and Manning close in on the end of their careers, it has been speculated that Seattle’s Wilson and San Francisco’s Kaepernick will provide the league with its next great quarterbacking rivalry.

Although they share a number of obvious traits – from their near-identical speed and similar playing styles right through to the fact that both slipped out of the first round of their respective drafts (Wilson actually lasted until mid-way through the third) – many people have instead chosen to dwell on the differences. Kaepernick, with his tattoos and his ostentatious touchdown celebrations has been portrayed as arrogant and self-centred, while Wilson is presented as the quiet and humble leader.

In the end neither side had proved anything at all, beyond the fact that people have too much time on their hands. Likewise, Kaepernick’s tattoo habit tells us nothing more than that he likes the way they look. The celebrations might betray a little something of the chip that he wears on his shoulder – the compulsive desire he feels to exact revenge on all those who have slighted him, and especially those teams who overlooked him in favour of another quarterback in the 2011 draft – but he has told us about that before.

We will learn more about the differences between Kaepernick and Wilson in the years to come, as their careers continue to develop. For now it is enough to know that they are two exceptionally talented young quarterbacks who happen to share a division. Given that they play for teams that already play twice a year and dislike one another a great deal, the rivalry should come as standard.

Whether or not it can eventually match the one created by Manning and Brady is, of course, another matter entirely. But it should be fun finding out.

NFL conference championships

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